The difficulty in falling asleep is because exercise raises your body temperature for two hours and you need a lower body temperature to sleep. I feel like weight lifting might produce less of this effect than cardio.
You say you work out from 6-8:30 PM. If that means "for an hour inside that time window", try to make sure you start at 6, not 8:30. If that means "I am working out for 2.5 hours continuously", you should shorten your workout. That long of a workout puts too much strain on your body and your long-term motivation. Some professional athletes work out less than that. Working out less should mean less stimulation and more time to cool down for sleep.
It won't hurt your results to exercise less, as long as you don't quit entirely. The calorie burn from exercise is not directly linked to weight loss. Typically your body just adjusts your hunger to make up for it. Exercise only helps by causing you to adopt the healthier eating patterns that reaching fitness goals requires.